Treatment of gasoline



Patented Nov. 2, 1943 versal Oil Products Company, corporation of Delaware Chicago, 111., a

No Drawing. Application May $1, 1940,

Serial No. 338,049

7 Claims. ((2144-72) a This invention relates to a method for improving the stability of hydrocarbon distillates in so far as color and gum formation are concerned. More particularly the process concerns improved methods of preventing deterioration of cracked gasoline which may be stored over relatively long periods of time in the presence of air, and is a continuation-in-part of my copending application Serial No. 321,571, filed February 29, 1940.

The use of inhibitors to prevent the depreciation of olefin-containing hydrocarbon distillates such as cracked gasoline has been practiced.

Such compounds as alkyl-substituted phenols,

aminophenols, fractions of wood tar distillates, etc., have been added to cracked gasoline in relatively minor quantities, oi! the order of 0.001- 0.l% to inhibit the formation of objectionable oxidation products and prevent loss of color and anti-knock properties of said gasolines during storage periods. The use of inhibitors has 'replaced or supplemented such forms of refining as acid-treating, clay-treating and the like. The result has been a material saving in refining costs as well as the conservation of substantial amounts of gasoline which were formerly lost in the refining steps. The present invention offers a means of improving the inhibiting properties of gasoline gum inhibitors and of efiecting material savings in the quantities of such materials which may be required adequately to preserve the valuable properties of gasoline,

In one specific embodiment the present invention comprises a method for treating hydrocarbon distillate such as cracked gasoline to preserve the valuable properties thereof by adding to saiddistillate a gasoline gum inhibitor, together with I a relatively minor quantity of a substituted alkylene diamine.

These compounds have the general structural formula:

R RI! I R!!! N(CHa)1+,(OH:)z'-N R H H wherein R is an alkyl group, R and R" may be an alkyl group or a hydrogen atom; wherein R' may be a hydrogen atom, an alkyl group or an aminoalkyl group; a: may be zero or an integer,

and :c' is an integer. Representative: compounds are N,N-diethyl ethylene diamine, N,N-di-nbutyl-ethylene diamine, N-ethyl-ethylene diamine, N-phenylethylene diamine, 4-(p-aminoethyl) -morpholine, N-ethyl-N'-fi-amino-ethylethylene diamine N-ethyl-N-p-aminoethyl ethylene diamine, and N,N-diethyl-N' -fl-aminoethyl ethylene diamine.

The compounds are used in combination with known gasoline gum inhibitors such as all-:yl

phenols, N -substituted alkylamino-phenols; substituted phenol ethers; fractions of hardwood tar I distillate boiling within the range of approximately, 240-280 C., and others. The compounds of this invention may be added to the gasoline separately or simultaneously with the gum inhibitor or may be previously mixed with the gum inhibitor and the mixture added to the gasoline. In any event, a relatively'minor amount of the compounds of this invention are added as compared with the gum inhibitor used. The exact quantity will be dependent to a large extent upon the gasoline being treated and to its response'to the action of gum inhibitors in general.

The quantity of alkylene diamine used in the gasoline is of the order of 0.0001-0.01%. The exact quantity required is a function 01 the inhibitor used and of the gasoline as well as the desired stability of the gasoline treated. The compounds of this invention are not of themselves gum inhibitors and the effect observed is not, therefore, such as might be expected by the mixing of two gasoline gum inhibitors. When added alone to cracked gasoline in amounts up to approximately 0.1%, little or no increase in the oxygen bomb induction period is to be observed and the storage tests indicate that no protection is obtained for the gasoline under storage conditions. However, when an inhibitor is added, the induction period with a given quantity of a gum inhibitor is markedly increased and with the more effective compounds of this invention, more than equal weight percentages of the inhibitor can be replaced without sufiering a loss of inhibitor potency. This will be brought out more fully in the examples to be given later.

The compounds of this invention are not necestive of the present invention. The oxygen bomb induction period of the various gasolines was determined. These are shown in the following table.

Oxy en bomb nduo- Compound added tion period Minutes It will be noted that in all cases the induction period of the gasoline is increased upon the addition of the compounds over that obtainable with the inhibitor alone. In all cases when the original gasoline was tested with these compounds in the absence of added gum inhibitor, no increase in induction period occurred, showing that the compounds themselves are not inhibitors, but that when used in conjunction with gum inhibitors they serve to increase the effectiveness thereof. Thus in order to obtain a given induction period, a smaller amount by weight of a mixture of the compounds of this invention with a gum inhibitor is required than would be required if the gum inhibitor alone were used.

I claim as my invention:

1. A method of treating cracked gasoline to prevent depreciation thereof which comprises adding to said gasoline a phenolic gum inhibitor and a compound of the following general structure:

wherein R is an alkyl group and :1: is an integer, the amount of said compound being insufiicient, in the absence of the inhibitor, to efiect any appreciable gum inhibition of the gasoline.

2. A method of treating cracked gasoline to prevent depreciation thereof which comprises adding to said gasoline a gasoline gum inhibitor and a compound having the following general structure:

wherein R, R and R" are alkyl groups and a: is an integer.

3. A method of treating cracked gasoline to prevent depreciation thereof which comprises adding to said gasoline a gasoline gum inhibitor and a compound of the following general structure:

wherein R and R are alkyl groups and :c is an integer.

4. A method of treating cracked gasoline to prevent depreciation thereof which comprises adding to said gasoline a gasoline gum inhibitor and a compound of the following general structure:

wherein R and R are alkyl groups and :1: is an integer.

5. In the stabilization of olefinic gasoline by the addition of phenolic gum inhibitors thereto. the method of increasing the effectiveness of the inhibitor which comprises incorporating into the gasoline, in addition to the phenolic inhibitor, an alkylene diamine in which a hydrogen atom of an amino group has been substituted by an alkyl group.

6. The method as defined in claim 5 further characterized in that said diamine is incorporated into the gasoline in the amount of approximately 0.0001-0.01%.

'7. A stabilizing agent for gum-forming gasoline comprising a phenolic gum inhibitor and an alkylene diamine in which a hydrogen atom of an amino group has been substituted by an' alkyl group.

JOSEPH A. CHIENICEK. 

